There's also a lot of fascinating information about the origins of agriculture (as well as the origins of writing, animal domestication, shipbuilding, nationstates, etc.) in the great book "Guns, Germs, and Steel: The fates of human societies", by Jared Diamond. I received this book for Christmas and hugely enjoyed it. It won the Pulitzer Prize, and I can certainly understand why. It's more informative (and a hell of a lot more interesting) than most college courses.